The correct answer is A. Adding facts and evidence
Explanation:
In language, it is recommended sentences explain clear and complete ideas. Additionally, in some cases, it is necessary to add evidence and facts to support and develop completely the main idea. In the case of the sentence, "Pollution levels in Beijing are improving in some ways thanks to government programs" this sentence is clear and somehow specific as it lets the reader know pollution is improving in a specific city (Beijing) and this is due to the government.
However, in this case, the author is not providing evidence about the programs implemented or the ways pollution is improving. Due to this, the best is to add facts and evidence because in this way the idea the sentence aims at explaining would be developed and supported appropriately.
